Cold and flu season hasn’t descended quite yet. But that doesn’t mean tots are immune from getting sick, especially with preschool gearing back up. Sore throats are especially common, but sometimes, it can be tough to know for sure whether your little one has a cough or strep. Here’s what you need to know.

Every year, 15 million Americans (kids and adults) visit their doctors complaining of a sore throat, and up to 70 percent of them receive an Rx for antibiotics. The problem? Most sore throats are caused by a virus, and antibiotics are useless—and potentially harmful—when used for viral infections. So the Infectious Diseases Society of America has just released new guidelines to tell the difference between a cough or strep throat.

“The goal is to reduce unnecessary antibiotic usage and prevent development of antibiotic resistance,” says the guidelines’ lead author Stanford T. Shulman, MD, professor of pediatrics at Northwestern University Feinberg School of Medicine in Chicago.

How to tell if your child has a cough or strep throat

In kids younger than 5, only 24 percent of sore throats turn out to be strep. So before your pediatrician grabs his prescription pad, consider your child’s symptoms. If she has a cough, runny nose, hoarseness and mouth sores, it’s likely viral. With strep, your child will have a fever and super-painful swallowing, but none of the viral symptoms. Also know that children younger than 3 rarely get strep; and that the white, pus-filled areas on tonsils (called exudates by docs) don’t automatically mean strep throat. “Viral infection can also be associated with exudates,” says Shulman.

When strep is suspected, the new guidelines recommend that your pediatrician swab your child’s throat and perform what’s called a rapid antigen detection test, which provides results in minutes. If the test is positive, your pediatrician should prescribe good old inexpensive penicillin or amoxicillin (for those who are not allergic), both of which have proven to be highly effective in combating strep.